Calculating Work Needed to Stop a 1100 kg Car | KE=1/2mv² | 118km/h Speed

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To calculate the work needed to stop a 1100 kg car traveling at 118 km/h, the kinetic energy (KE) formula is applied: KE = 1/2 mv². The speed conversion from km/h to m/s yields approximately 32.78 m/s. Plugging this value into the KE formula results in a kinetic energy of about 118,181,537.9 joules. The work done to stop the car is equal to this kinetic energy, which means approximately -5.91 x 10^7 joules of work is required. Accurate unit conversions and calculations are crucial for determining the correct amount of work needed.
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Homework Statement



How much work must be done to stop a 1100 kg car traveling at 118 km/hr?

Homework Equations


Ei + W= Ef
KE= 1/2mv^2

The Attempt at a Solution



KE= 1/2mv^2

118kmx1000m/360s= 327.78

327.78^2= 107437.76

107437.76x1100= 118181537.9

118181537.9/2 = -5.91x10^7

thanks for any help
 
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lim said:
118kmx1000m/360s= 327.78
Recheck that conversion: How many seconds in an hour?
 
do KE = 1/2 (1100 kg)(118*(1000/3600))^2
 

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